Embodiments of the inventive concept relate to an image sensor, and more particularly, to an image sensor for reducing peak current by controlling counters in a plurality of groups.
An image sensor is a device that captures a two-dimensional or a three-dimensional image of an object. The image sensor generates the image of an object using a photoelectric conversion element, which reacts to the intensity of light reflected from the object. Recently, with the development of complementary metal-oxide semiconductor (CMOS) technology, use of CMOS image sensors has increased significantly.
A CMOS image sensor uses correlated double sampling (CDS) for image capturing, counts a sampled signal resulting from the CDS, e.g., a difference between a reset signal and an image signal, and outputs a digital signal corresponding to a count result. Power is consumed during the counting, and during a certain period, e.g., during multi-bit toggling, high peak current may occur. Peak current higher than a predetermined level may degrade the quality of pixel data and cause malfunctions in the system. For example, when multiple bits are toggled with respect to data output from each column in an image sensor, multiple column counters simultaneously toggle, causing peak current to occur. A high peak current affects results of reading out pixel data, deteriorating data quality. Accordingly, technology for preventing or reducing high peak current is needed.